# ST3421SRG

**STANSON Tech** · MOSFETs · SOT-23

ST3421SRG from STANSON Tech, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | Gate | input | Gate of the P-channel enhancement MOSFET; the gate-source voltage is rated ±20 V (VGSS). |
| 2 | Source | passive | Source of the P-channel MOSFET; the continuous source current (diode conduction) is rated -1.25 A (IS). |
| 3 | Drain | passive | Drain of the P-channel MOSFET; the drain-source voltage is rated -60 V (VDSS) with continuous drain current -5.0 A at TA=25°C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STANSON Tech |
| Package | SOT-23 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Drain-Source Voltage | VDSS |  |  | -60 | V |  | 2 |
| Gate-Source Voltage | VGSS | -20 |  | 20 | V |  | 2 |
| Continuous Drain Current | ID |  |  | -5 | A | TA=25℃ | 2 |
| Continuous Drain Current | ID |  |  | -3.5 | A | TA=70℃ | 2 |
| Pulsed Drain Current | IDM |  |  | -12 | A |  | 2 |
| Continuous Source Current (Diode Conduction) | IS |  |  | -1.25 | A |  | 2 |
| Power Dissipation | PD |  |  | 1.25 | W | TA=25℃ | 2 |
| Power Dissipation | PD |  |  | 0.8 | W | TA=70℃ | 2 |
| Operation Junction Temperature | TJ |  |  | 150 | ℃ |  | 2 |
| Storage Temperature Range | TSTG | -55 |  | 150 | ℃ |  | 2 |
| Thermal Resistance-Junction to Ambient | RθJA |  | 100 |  | ℃/W |  | 2 |
| Drain-Source Breakdown Voltage | V(BR)DSS | -60 |  |  | V | VGS=0V,ID=-10uA | 3 |
| Gate Threshold Voltage | VGS(th) | -1 |  | -3 | V | VDS=VGS,ID=-250uA | 3 |
| Gate Leakage Current | IGSS | -100 |  | 100 | nA | VDS=0V,VGS=±20V | 3 |
| Zero Gate Voltage Drain Current | IDSS |  |  | -1 | uA | VDS=-48V,VGS=0V | 3 |
| Zero Gate Voltage Drain Current | IDSS |  |  | -10 | uA | VDS=-48V,VGS=0V, TJ=55℃ | 3 |
| Drain-source On-Resistance | RDS(on) |  | 0.15 | 0.16 | Ω | VGS=-10V,ID=-5.0A | 3 |
| Drain-source On-Resistance | RDS(on) |  | 0.185 | 0.2 | Ω | VGS=-4.5V,ID=-2.5A | 3 |
| Forward Transconductance | gfs | 2.4 |  |  | S | VDS=-10V,ID=-1.7V | 3 |
| Diode Forward Voltage | VSD |  | -0.8 | -1.2 | V | IS=-1.25A,VGS=0V | 3 |

## CAD (KiCad official)

- Symbol: `ST3421SRG`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `st3421srg-etched.step` / `st3421srg-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `st3421srg.step` / `st3421srg.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [STANSON Tech datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588911328752766976) (6 pp, sha256 `66bb654dd810f77f`, retrieved 2026-10-09, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/st3421srg-datasheet.pdf)